Showing papers in "Journal of Dental Research in 2011"
TL;DR: The what, why, and how of OHRQoL is identified and an oral health theoretical model is presented and the relevance for dental practitioners and patients in community-based dental practices is presented.
Abstract: Despite its relatively recent emergence over the past few decades, oral health-related quality of life (OHRQoL) has important implications for the clinical practice of dentistry and dental research. OHRQoL is a multidimensional construct that includes a subjective evaluation of the individual's oral health, functional well-being, emotional well-being, expectations and satisfaction with care, and sense of self. It has wide-reaching applications in survey and clinical research. OHRQoL is an integral part of general health and well-being. In fact, it is recognized by the World Health Organization (WHO) as an important segment of the Global Oral Health Program (2003). This paper identifies the what, why, and how of OHRQoL and presents an oral health theoretical model. The relevance of OHRQoL for dental practitioners and patients in community-based dental practices is presented. Implications for health policy and related oral health disparities are also discussed. A supplemental Appendix contains a Medline and ProQuest literature search regarding OHRQoL research from 1990-2010 by discipline and research design (e.g., descriptive, longitudinal, clinical trial, etc.). The search identified 300 articles with a notable surge in OHRQoL research in pediatrics and orthodontics in recent years.
1,106 citations
TL;DR: Environmental acidification is the main determinant of the phenotypic and genotypic changes that occur in the microflora during caries.
Abstract: Dental biofilms produce acids from carbohydrates that result in caries. According to the extended caries ecological hypothesis, the caries process consists of 3 reversible stages. The microflora on clinically sound enamel surfaces contains mainly non-mutans streptococci and Actinomyces, in which acidification is mild and infrequent. This is compatible with equilibrium of the demineralization/remineralization balance or shifts the mineral balance toward net mineral gain (dynamic stability stage). When sugar is supplied frequently, acidification becomes moderate and frequent. This may enhance the acidogenicity and acidurance of the non-mutans bacteria adaptively. In addition, more aciduric strains, such as ‘low-pH’ non-mutans streptococci, may increase selectively. These microbial acid-induced adaptation and selection processes may, over time, shift the demineralization/remineralization balance toward net mineral loss, leading to initiation/progression of dental caries (acidogenic stage). Under severe and p...
923 citations
TL;DR: The general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance are reviewed.
Abstract: Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance.
570 citations
TL;DR: Five experimental strategies developed by different research groups for extending the longevity of resin-dentin bonds are examined, finding a combination of several of these strategies should result in overcoming the critical barriers to progress currently encountered in dentin bonding.
Abstract: The limited durability of resin-dentin bonds severely compromises the lifetime of tooth-colored restorations Bond degradation occurs via hydrolysis of suboptimally polymerized hydrophilic resin components and degradation of water-rich, resin-sparse collagen matrices by matrix metalloproteinases (MMPs) and cysteine cathepsins This review examined data generated over the past three years on five experimental strategies developed by different research groups for extending the longevity of resin-dentin bonds They include: (1) increasing the degree of conversion and esterase resistance of hydrophilic adhesives; (2) the use of broad-spectrum inhibitors of collagenolytic enzymes, including novel inhibitor functional groups grafted to methacrylate resins monomers to produce anti-MMP adhesives; (3) the use of cross-linking agents for silencing the activities of MMP and cathepsins that irreversibly alter the 3-D structures of their catalytic/allosteric domains; (4) ethanol wet-bonding with hydrophobic resins to completely replace water from the extrafibrillar and intrafibrillar collagen compartments and immobilize the collagenolytic enzymes; and (5) biomimetic remineralization of the water-filled collagen matrix using analogs of matrix proteins to progressively replace water with intrafibrillar and extrafibrillar apatites to exclude exogenous collagenolytic enzymes and fossilize endogenous collagenolytic enzymes A combination of several of these strategies should result in overcoming the critical barriers to progress currently encountered in dentin bonding
560 citations
TL;DR: The ability of TLRs to engage different intracellular signaling molecules and cross-talk with other regulatory pathways is an important factor in shaping the type, magnitude, and duration of the inflammatory response as discussed by the authors.
Abstract: Toll-like receptors play a critical role in innate immunity by detecting invading pathogens. The ability of TLRs to engage different intracellular signaling molecules and cross-talk with other regulatory pathways is an important factor in shaping the type, magnitude, and duration of the inflammatory response. The present review will cover the fundamental signaling pathways utilized by TLRs and how these pathways regulate the innate immune response to pathogens. Abbreviations: TLR, Toll-like receptor; PRR, pattern recognition receptor; PAMP, pathogen-associated molecular pattern; LPS, lipopolysaccharide; APC, antigen-presenting cell; IL, interleukin; TIR, Toll/IL-1R homology; MyD88, myeloid differentiation factor 88; IFN, interferon; TRIF, TIR-domain-containing adapter-inducing interferon-β; IRAK, IL-1R-associated kinase; TAK1, TGF-β-activated kinase; TAB1, TAK1-binding protein; NF-κB, nuclear factor kappa-light-chain-enhancer of activated B-cells; MAPK, mitogen-activated protein kinase; NLR, NOD-like rece...
457 citations
TL;DR: Clinical, experimental, and analytic results reported in the recent literature are summarized to address how this new information adds insight into predictive test procedures and reveals challenges for future improvements.
Abstract: The clinical success of modern dental ceramics depends on an array of factors, ranging from initial physical properties of the material itself, to the fabrication and clinical procedures that inevitably damage these brittle materials, and the oral environment. Understanding the influence of these factors on clinical performance has engaged the dental, ceramics, and engineering communities alike. The objective of this review is to first summarize clinical, experimental, and analytic results reported in the recent literature. Additionally, it seeks to address how this new information adds insight into predictive test procedures and reveals challenges for future improvements.
328 citations
TL;DR: Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations that can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization.
Abstract: Fluorides are present in the environment. Excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis (skeletal fluorosis) and enamel development (dental/enamel fluorosis). The severity of dental fluorosis is also dependent upon fluoride dose and the timing and duration of fluoride exposure. Fluoride's actions on bone cells predominate as anabolic effects both in vitro and in vivo. More recently, fluoride has been shown to induce osteoclastogenesis in mice. Fluorides appear to mediate their actions through the MAPK signaling pathway and can lead to changes in gene expression, cell stress, and cell death. Different strains of inbred mice demonstrate differential physiological responses to ingested fluoride. Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations. Ultimately, this can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization.
298 citations
TL;DR: The effect of a given mediator is dependent upon the temporal context in which it is expressed, and better understanding of this temporal sequence may be used to optimize regenerative outcomes.
Abstract: Various strategies have been developed to promote bone regeneration in the craniofacial region. Most of these interventions utilize implantable materials or devices. Infections resulting from colonization of these implants may result in local tissue destruction in a manner analogous to periodontitis. This destruction is mediated via the expression of various inflammatory mediators and tissue-destructive enzymes. Given the well-documented association among microbial biofilms, inflammatory mediators, and tissue destruction, it seems reasonable to assume that inflammation may interfere with bone healing and regeneration. Paradoxically, recent evidence also suggests that the presence of certain pro-inflammatory mediators is actually required for bone healing. Bone injury (e.g., subsequent to a fracture or surgical intervention) is followed by a choreographed cascade of events, some of which are dependent upon the presence of pro-inflammatory mediators. If inflammation resolves promptly, then proper bone healing may occur. However, if inflammation persists (which might occur in the presence of an infected implant or graft material), then the continued inflammatory response may result in suboptimal bone formation. Thus, the effect of a given mediator is dependent upon the temporal context in which it is expressed. Better understanding of this temporal sequence may be used to optimize regenerative outcomes.
267 citations
TL;DR: Findings are consistent with the hypothesis that trigeminal neurons are capable of detecting pathogenic bacterial components leading to sensitization of TRPV1, possibly contributing to the inflammatory pain often observed in bacterial infections.
Abstract: Recent studies have demonstrated that the lipopolysaccharide (LPS) receptor (TLR4) is expressed in TRPV1 containing trigeminal sensory neurons. In this study, we evaluated whether LPS activates trigeminal neurons, and sensitizes TRPV1 responses via TLR4. To test this novel hypothesis, we first demonstrated that LPS binds to receptors in trigeminal neurons using competitive binding. Second, we demonstrated that LPS evoked aconcentration-dependent increase in intracellular calcium accumulation (Ca2+)i and inward currents. Third, LPS significantly sensitized TRPV1 to capsaicin measured by (Ca2+)i, release of calcitonin gene-related peptide, and inward currents. Importantly, a selective TLR4 antagonist blocked these effects. Analysis of these data, collectively, demonstrates that LPS is capable of directly activating trigeminal neurons, and sensitizing TRPV1 via a TLR4-mediated mechanism. These findings are consistent with the hypothesis that trigeminal neurons are capable of detecting pathogenic bacterial co...
248 citations
TL;DR: This review summarizes the current knowledge about epigenetic control mechanisms during the inflammatory response and investigates the role of methylation and acetylation in the modulation of inflammatory and anti-inflammatory genes.
Abstract: Epigenetic modifications occur in response to environmental changes and play a fundamental role in gene expression following environmental stimuli. Major epigenetic events include methylation and acetylation of histones and regulatory factors, DNA methylation, and small non-coding RNAs. Diet, pollution, infections, and other environmental factors have profound effects on epigenetic modifications and trigger susceptibility to diseases. Despite a growing body of literature addressing the role of the environment on gene expression, very little is known about the epigenetic pathways involved in the modulation of inflammatory and anti-inflammatory genes. This review summarizes the current knowledge about epigenetic control mechanisms during the inflammatory response.
241 citations
TL;DR: A proposal is made that periodontal inflammation not only stimulates osteoclastogenesis but also interferes with the uncoupling of bone formation and bone resorption, consistent with a pathologic process, and arguments based on experimental animal models suggest a critical role of the spatial and temporal aspects of inflammation in the periodontium.
Abstract: Periodontal disease is characterized by both inflammation and bone loss. Advances in research in both these areas have led to a new appreciation of not only each field but also the intimate relationship between inflammation and bone loss. This relationship has resulted in a new field of science called osteoimmunology and provides a context for better understanding the pathogenesis of periodontal disease. In this review, we discuss several aspects of the immuno-inflammatory host response that ultimately results in loss of alveolar bone. A proposal is made that periodontal inflammation not only stimulates osteoclastogenesis but also interferes with the uncoupling of bone formation and bone resorption, consistent with a pathologic process. Furthermore, arguments based on experimental animal models suggest a critical role of the spatial and temporal aspects of inflammation in the periodontium. A review of these findings leads to a new paradigm to help explain more fully the impact of inflammation on alveolar bone in periodontal disease so that it includes the effects of inflammation on uncoupling of bone formation from resorption.
TL;DR: Twitter users extensively share health information relating to dental pain, including actions taken to relieve pain and the impact of pain, and this new medium may provide an opportunity for dental professionals to disseminate health information.
Abstract: On Twitter, people answer the question, “What are you doing right now?” in no more than 140 characters. We investigated the content of Twitter posts meeting search criteria relating to dental pain. A set of 1000 tweets was randomly selected from 4859 tweets over 7 non-consecutive days. The content was coded using pre-established, non-mutually-exclusive categories, including the experience of dental pain, actions taken or contemplated in response to a toothache, impact on daily life, and advice sought from the Twitter community. After excluding ambiguous tweets, spam, and repeat users, we analyzed 772 tweets and calculated frequencies. Of the sample of 772 tweets, 83% (n = 640) were primarily categorized as a general statement of dental pain, 22% (n = 170) as an action taken or contemplated, and 15% (n = 112) as describing an impact on daily activities. Among the actions taken or contemplated, 44% (n = 74) reported seeing a dentist, 43% (n = 73) took an analgesic or antibiotic medication, and 14% (n = 24) actively sought advice from the Twitter community. Twitter users extensively share health information relating to dental pain, including actions taken to relieve pain and the impact of pain. This new medium may provide an opportunity for dental professionals to disseminate health information.
TL;DR: In this paper, the relative effectiveness of fluoride toothpastes of different concentrations in preventing dental caries in children and adolescents was evaluated using a network meta-analysis utilizing both direct and indirect comparisons from randomized controlled trials (RCTs).
Abstract: This concise review presents two Cochrane Reviews undertaken to determine: (1) the relative effectiveness of fluoride toothpastes of different concentrations in preventing dental caries in children and adolescents; and (2) the relationship between the use of topical fluorides in young children and their risk of developing dental fluorosis. To determine the relative effectiveness of fluoride toothpastes of different concentrations, we undertook a network meta-analysis utilizing both direct and indirect comparisons from randomized controlled trials (RCTs). The review examining fluorosis included evidence from experimental and observational studies. The findings of the reviews confirm the benefits of using fluoride toothpaste, when compared with placebo, in preventing caries in children and adolescents, but only significantly for fluoride concentrations of 1000 ppm and above. The relative caries-preventive effects of fluoride toothpastes of different concentrations increase with higher fluoride concentration. However, there is weak, unreliable evidence that starting the use of fluoride toothpaste in children under 12 months of age may be associated with an increased risk of fluorosis. The decision of what fluoride levels to use for children under 6 years should be balanced between the risk of developing dental caries and that of mild fluorosis.
TL;DR: The results indicate that, along with MMPs, cysteine cathepsins are important, especially in active and deep caries.
Abstract: Matrix metalloproteinases (MMPs) are important in dentinal caries, and analysis of recent data demonstrates the presence of other collagen-degrading enzymes, cysteine cathepsins, in human dentin. This study aimed to examine the presence, source, and activity of cysteine cathepsins in human caries. Cathepsin B was detected with immunostaining. Saliva and dentin cysteine cathepsin and MMP activities on caries lesions were analyzed spectrofluorometrically. Immunostaining demonstrated stronger cathepsins B in carious than in healthy dentin. In carious dentin, cysteine cathepsin activity increased with increasing depth and age in chronic lesions, but decreased with age in active lesions. MMP activity decreased with age in both active and chronic lesions. Salivary MMP activities were higher in patients with active than chronic lesions and with increasing lesion depth, while cysteine cathepsin activities showed no differences. The results indicate that, along with MMPs, cysteine cathepsins are important, especially in active and deep caries.
Osaka University1, Kagoshima University2, Nagasaki University3, Fukuoka Dental College4, Kyushu University5, Kyushu Dental University6, University of Tokushima7, Hiroshima University8, Okayama University9, Asahi University10, Aichi Gakuin University11, Niigata University12, Tsurumi University13, Keio University14, Nihon University15, Tokyo Medical and Dental University16, Tohoku University17, Iwate Medical University18, Hokkaido University19, Health Sciences University of Hokkaido20, Nagoya University21
TL;DR: Results strongly suggest that topical application of FGF-2 can be efficacious in the regeneration of human periodontal tissue that has been destroyed by periodontitis.
Abstract: The efficacy of the local application of recombinant human fibroblast growth factor-2 (FGF-2) in periodontal regeneration has been investigated. In this study, a randomized, double-blind, placebo-controlled clinical trial was conducted in 253 adult patients with periodontitis. Modified Widman periodontal surgery was performed, during which 200 µL of the investigational formulation containing 0% (vehicle alone), 0.2%, 0.3%, or 0.4% FGF-2 was administered to 2- or 3-walled vertical bone defects. Each dose of FGF-2 showed significant superiority over vehicle alone (p < 0.01) for the percentage of bone fill at 36 wks after administration, and the percentage peaked in the 0.3% FGF-2 group. No significant differences among groups were observed in clinical attachment regained, scoring approximately 2 mm. No clinical safety problems, including an abnormal increase in alveolar bone or ankylosis, were identified. These results strongly suggest that topical application of FGF-2 can be efficacious in the regeneration of human periodontal tissue that has been destroyed by periodontitis.
TL;DR: The molecular basis of low-grade, unresolved, subclinical inflammation as a major risk factor for exacerbating the aging process and age-related diseases is explored and redox-sensitive transcription factors, NF-κB and FOXO, play essential roles in the expression of pro-inflammatory mediators and anti-oxidant enzymes.
Abstract: Aging is a biological process characterized by time-dependent functional declines that are influenced by changes in redox status and by oxidative stress-induced inflammatory reactions. An organism's pro-inflammatory status may underlie the aging process and age-related diseases. In this review, we explore the molecular basis of low-grade, unresolved, subclinical inflammation as a major risk factor for exacerbating the aging process and age-related diseases. We focus on the redox-sensitive transcription factors, NF-κB and FOXO, which play essential roles in the expression of pro-inflammatory mediators and anti-oxidant enzymes, respectively. Major players in molecular inflammation are discussed with respect to the age-related up-regulation of pro-inflammatory cytokines and adhesion molecules, cyclo-oxygenase-2, lipoxygenase, and inducible nitric oxide synthase. The molecular inflammation hypothesis proposed by our laboratory is briefly described to give further molecular insights into the intricate interplay among redox balance, pro-inflammatory gene activation, and chronic age-related inflammatory diseases. The final section discusses calorie restriction as an aging-retarding intervention that also exhibits extraordinarily effective anti-inflammatory activity by modulating GSH redox, NF-κB, SIRT1, PPARs, and FOXOs.
TL;DR: In this paper, the authors summarize periodontopathic bacteria and host factors, including infiltrating cell populations, cytokines, and host matrix metalloproteinases, associated with undergoing episodic attachment loss that could partly explain the mechanisms involved in destruction of the supporting tissues of the tooth.
Abstract: Periodontitis is an infection characterized by the occurrence of supporting tissue destruction with an episodic nature. Disease progression is often determined by the loss of attachment level or alveolar bone, and sequential probing of periodontal attachment remains the most commonly utilized method to diagnose progressive destruction of the periodontium. The tolerance method has been the most extensive clinical method used in recent years to determine site-specific attachment level changes. There is abundant evidence that major tissue destruction in periodontal lesions results from the recruitment of immune cells. Considerable effort has been made to study the host cell and mediator profiles involved in the pathogenesis of chronic periodontitis, but the definition of active sites, where current periodontal breakdown occurs, and consecutive characterization of the mediators involved are still among the main concerns. In the present review, we summarize periodontopathic bacteria and host factors, including infiltrating cell populations, cytokines, and host matrix metalloproteinases, associated with under-going episodic attachment loss that could partly explain the mechanisms involved in destruction of the supporting tissues of the tooth.
TL;DR: Both IV and oral bisphosphonate use were strongly associated with ONJ; duration of treatment > 2 years; suppuration and dental extractions were independent risk factors for ONJ.
Abstract: Case reports and cohort studies have linked bisphosphonate therapy and osteonecrosis of the jaws (ONJ), but neither causality nor specific risks for lesion development have been clearly established. We conducted a 1:3 case-control study with three dental Practice-based Research Networks, using dentist questionnaires and patient interviews for collection of data on bisphosphonate therapy, demographics, co-morbidities, and dental and medical treatments. Multivariable logistic regression analyses tested associations between bisphosphonate use and other risk factors with ONJ. We enrolled 191 ONJ cases and 573 controls in 119 dental practices. Bisphosphonate use was strongly associated with ONJ (odds ratios [OR] 299.5 {95%CI 70.0-1282.7} for intravenous [IV] use and OR = 12.2 {4.3-35.0} for oral use). Risk markers included local suppuration (OR = 7.8 {1.8-34.1}), dental extraction (OR = 7.6 {2.4-24.7}), and radiation therapy (OR = 24.1 {4.9-118.4}). When cancer patients (n = 143) were excluded, bisphosphonate use (OR = 7.2 {2.1-24.7}), suppuration (OR = 11.9 {2.0-69.5}), and extractions (OR = 6.6 {1.6-26.6}) remained associated with ONJ. Higher risk of ONJ began within 2 years of bisphosphonate initiation and increased four-fold after 2 years. Both IV and oral bisphosphonate use were strongly associated with ONJ. Duration of treatment > 2 years; suppuration and dental extractions were independent risk factors for ONJ.
TL;DR: Ex vivo delivery of bFGF induced re-cellularization and re-vascularization in endodontically treated human teeth implanted into the dorsum of rats indicates that endogenous dental pulp cells, including stem/progenitor cells, may be recruited and subsequently differentiated by chemotaxis of selective cytokines in the regeneration of dental pulp.
Abstract: Dental pulp has intrinsic capacity for self-repair. However, it is not clear whether dental pulp cells can be recruited endogenously for regenerating pulp tissues, including mineralizing into dentin. This work is based on a hypothesis that dental pulp stem/progenitor cells can be induced to migrate by chemotactic cytokines and act as endogenous cell sources for regeneration and mineralization. Dental stem cells (DSCs) were isolated from adult human tooth pulp and seeded on the surfaces of 3D collagen gel cylinders that were incubated in chemically defined media with stromal-derived factor-1α (SDF1), basic fibroblast growth factor (bFGF), or bone morphogenetic protein-7 (BMP7). Significantly more cells were recruited into collagen gel by SDF1 or bFGF than without cytokines in 7 days, whereas BMP7 had little effect on cell recruitment. BMP7, however, was highly effective, equally to dexamethasone, in orchestrating mineralization of cultured DSCs. Cell membrane receptors for SDF1, bFGF, and BMP7 were up-regulated in treated DSCs. Upon in vivo delivery, bFGF induced re-cellularization and re-vascularization in endodontically treated human teeth implanted into the dorsum of rats. Thus, endogenous dental pulp cells, including stem/progenitor cells, may be recruited and subsequently differentiated by chemotaxis of selective cytokines in the regeneration of dental pulp.
TL;DR: The use of salivary and biofilm biomarkers offers potential for the identification of PDP or stability (ClinicalTrials.gov number, CT00277745) and the association of cluster membership to PDP was highly significant (p < 0.0002).
Abstract: The purpose of this study was to determine the role of saliva-derived biomarkers and periodontal pathogens during periodontal disease progression (PDP). One hundred human participants were recruited into a 12-month investigation. They were seen bi-monthly for saliva and clinical measures and bi-annually for subtraction radiography, serum and plaque biofilm assessments. Saliva and serum were analyzed with protein arrays for 14 pro-inflammatory and bone turnover markers, while qPCR was used for detection of biofilm. A hierarchical clustering algorithm was used to group study participants based on clinical, microbiological, salivary/serum biomarkers, and PDP. Eighty-three individuals completed the six-month monitoring phase, with 39 [corrected] exhibiting PDP, while 44 [corrected] demonstrated stability. Participants assembled into three clusters based on periodontal pathogens, serum and salivary biomarkers. Cluster 1 members displayed high salivary biomarkers and biofilm; 71% [corrected] of these individuals were undergoing PDP. Cluster 2 members displayed low biofilm and biomarker levels; 76% [corrected] of these individuals were stable. Cluster 3 members were not discriminated by PDP status; however, cluster stratification followed groups 1 and 2 based on thresholds of salivary biomarkers and biofilm pathogens. The association of cluster membership to PDP was highly significant (p < 0.0007). [corrected] The use of salivary and biofilm biomarkers offers potential for the identification of PDP or stability (ClinicalTrials.gov number, CT00277745).
TL;DR: Differences in the oral microbiota in infants due to mode of delivery are indicated, with vaginally delivered infants having a higher number of taxa detected by the HOMIM microarray.
Abstract: Establishment of the microbiota of the gut has been shown to differ between infants delivered by Caesarian section (C-section) and those delivered vaginally. The aim of the present study was to compare the oral microbiota in infants delivered by these different routes. The oral biofilm was assayed by the Human Oral Microbe Identification Microarray (HOMIM) in healthy three-month-old infants, 38 infants born by C-section, and 25 infants delivered vaginally. Among over 300 bacterial taxa targeted by the HOMIM microarray, Slackia exigua was detected only in infants delivered by C-section. Further, significantly more bacterial taxa were detected in the infants delivered vaginally (79 species/species clusters) compared with infants delivered by C-section (54 species/species clusters). Multivariate modeling revealed a strong model that separated the microbiota of C-section and vaginally delivered infants into two distinct colonization patterns. In conclusion, our study indicated differences in the oral microbiota in infants due to mode of delivery, with vaginally delivered infants having a higher number of taxa detected by the HOMIM microarray.
TL;DR: Analysis of the data suggests that oral healthcare professionals have the opportunity to identify unrecognized diabetes and pre-diabetes in dental patients and refer them to a physician for further evaluation and care.
Abstract: Many diabetic patients remain undiagnosed, and oral findings may offer an unrealized opportunity for the identification of affected individuals unaware of their condition. We recruited 601 individuals who presented for care at a dental clinic, were ≥40 years old, if non-Hispanic white, and ≥30 years old, if Hispanic or non-white, and had never been told they have pre-diabetes or diabetes. Those with at least one self-reported diabetes risk factor (N=535) received a periodontal examination and a point-of-care hemoglobin A1c (HbA1c) test. A fasting plasma glucose (FPG) test was used as the study outcome, signifying potential diabetes or pre-diabetes. Performance characteristics of simple models of dysglycemia (FPG≥100 mg/dL) identification were evaluated and optimal cut-offs identified. A model including only two dental variables had an estimated area under the receiver operating characteristic curve (AUC) of 0.65. The addition of a point-of-care HbA1c test improved the AUC to 0.79 (p<0.001). The presence of ≥26% deep pockets or ≥4 missing teeth correctly identified 73% of true cases; the addition of an HbA1c≥5.7% increased correct identification to 92%. Analysis of our data suggests that oral healthcare professionals have the opportunity to identify unrecognized diabetes and pre-diabetes in dental patients and refer them to a physician for further evaluation and care.
TL;DR: Several species, including S. wiggsiae and S. exigua, are associated with the ecology of advanced caries, that successful treatment is accompanied by a change in the microbiota, and that severe ECC is diverse, with influences from selected bacteria or from diet.
Abstract: Severe early childhood caries (ECC) is difficult to treat successfully. This study aimed to characterize the microbiota of severe ECC and evaluate whether baseline or follow-up microbiotas are associated with new lesions post-treatment. Plaque samples from 2- to 6-year-old children were analyzed by a 16S rRNA-based microarray and by PCR for selected taxa. Severe-ECC children were monitored for 12 months post-therapy. By microarray, species associated with severe-ECC (n = 53) compared with caries-free (n = 32) children included Slackia exigua (p = 0.002), Streptococcus parasanguinis (p = 0.013), and Prevotella species (p < 0.02). By PCR, severe-ECC-associated taxa included Bifidobacteriaceae (p < 0.001), Scardovia wiggsiae (p = 0.003), Streptococcus mutans with bifidobacteria (p < 0.001), and S. mutans with S. wiggsiae (p = 0.001). In follow-up, children without new lesions (n = 36) showed lower detection of taxa including S. mutans, changes not observed in children with follow-up lesions (n = 17). Partial least-squares modeling separated the children into caries-free and two severe-ECC groups with either a stronger bacterial or a stronger dietary component. We conclude that several species, including S. wiggsiae and S. exigua, are associated with the ecology of advanced caries, that successful treatment is accompanied by a change in the microbiota, and that severe ECC is diverse, with influences from selected bacteria or from diet.
TL;DR: There is compelling evidence that treponemes are involved in the etiology of several chronic diseases, including chronic periodontitis as well as other forms ofperiodontal disease, and recent animal studies indicate that co-infection of Treponema denticola with other periodontal pathogens can enhance alveolar bone resorption.
Abstract: There is compelling evidence that treponemes are involved in the etiology of several chronic diseases, including chronic periodontitis as well as other forms of periodontal disease. There are interesting parallels with other chronic diseases caused by treponemes that may indicate similar virulence characteristics. Chronic periodontitis is a polymicrobial disease, and recent animal studies indicate that co-infection of Treponema denticola with other periodontal pathogens can enhance alveolar bone resorption. The bacterium has a suite of molecular determinants that could enable it to cause tissue damage and subvert the host immune response. In addition to this, it has several non-classic virulence determinants that enable it to interact with other pathogenic bacteria and the host in ways that are likely to promote disease progression. Recent advances, especially in molecular-based methodologies, have greatly improved our knowledge of this bacterium and its role in disease.
TL;DR: Sealing in caries by the Hall Technique statistically, and clinically, significantly outperformed GDPs’ standard restorations in the long term (Trial registration no. ISRCTN 47267892).
Abstract: The Hall Technique (HT) is a method for managing carious primary molars. Decay is sealed under pre-formed metal crowns without any caries removal, tooth preparation, or local anesthesia. The aim of this study was to compare HT clinical/radiographic failure rates with General Dental Practitioners' (GDPs) standard (control) restorations. We conducted a split-mouth, randomized control trial (132 children, aged 3-10 yrs, GDPs n = 17) in Scotland. There were 264 study teeth with initial lesions, 42% of which were radiographically > half-way into dentin, and 67% of which had Class II restorations. Teeth were randomized to HT (intervention) or GDPs' usual treatment (control). Annual clinical/radiographic follow-up data were recorded. Ninety-one patients (69%) had 48 months' minimum follow-up. At 60 months, 'Major' failures (irreversible pulpitis, loss of vitality, abscess, or unrestorable tooth) were recorded: HT, 3 (3%); control restorations, 15 (16.5%) (p = 0.000488; NNT 8); and 'Minor' failures (reversible pulpitis, restoration loss/wear/fracture; or secondary caries): HT, 4 (5%); control restorations, 38 (42%) (p < 0.000001; NNT 3). Overall, there were follow-up data for 130 patients (2-60 mos): 'Major' failures: HT, 3 (2%); control restorations, 22 (17%) (p = 0.000004; NNT 7); and 'Minor' failures, HT, 7 (5%); control restorations, 60 (46%) (p < 0.000001; NNT 3). Sealing in caries by the Hall Technique statistically, and clinically, significantly outperformed GDPs' standard restorations in the long term (Trial registration no. ISRCTN 47267892).
TL;DR: It is concluded that QAMs exhibited dentin MMP inhibition comparable with that of chlorhexidine, but required higher concentrations.
Abstract: Matrix metalloproteinases (MMPs) bound to dentin contribute to the progressive degradation of collagen fibrils in hybrid layers created by dentin adhesives. This study evaluated the MMP-inhibiting potential of quaternary ammonium methacrylates (QAMs), with soluble rhMMP-9 and a matrix-bound endogenous MMP model. Six different QAMs were initially screened by a rhMMP-9 colorimetric assay. For the matrix-bound endogenous MMPs, we aged demineralized dentin beams for 30 days in calcium- and zinc-containing media (CM; control), chlorhexidine, or QAMs in CM to determine the changes in dry mass loss and solubilization of collagen peptides against baseline levels. The inhibitory effects of QAMs on soluble rhMMP-9 varied between 34 and 100%. Beams incubated in CM showed a 29% decrease in dry mass (p < 0.05), whereas beams incubated with QAMs showed only 0.2%-6% loss of dry mass. Significantly more solubilized collagen was detected from beams incubated in CM (p < 0.05). It is concluded that QAMs exhibited dentin MMP inhibition comparable with that of chlorhexidine, but required higher concentrations.
TL;DR: Evidence is provided that each individual, in the natural environment, chews with a consistent pace across different days, as assessed in thenatural environment.
Abstract: The aim of this observational study was to investigate the features of the chewing activity and the variability of the human chewing pace, as assessed in the natural environment. It was hypothesized that the chewing pace is relatively constant within individuals across different days but is variable across individuals. Electromyographic surface activity was recorded unilaterally from the masseter in 21 participants for 3 hours over 3 recording days, in the natural environment, by means of portable recorders. The time-frequency properties of chewing activity were assessed with a previously validated algorithm. Repeated-measurements ANOVA was used for statistical analysis. Chewing activity mainly occurred in the range of 0.94 Hz (5th percentile) and 2.17 Hz (95th percentile). Mean and median chewing frequencies were 1.57 Hz and 1.58 Hz, respectively (95% confidence intervals: 1.45-1.68 Hz). The mean duration of chewing episodes was 13.0 sec, the 5th and 95th percentiles being 2.7 sec and 34.9 sec, respectiv...
TL;DR: There is considerable income-related inequality in dental service utilization by several elderly populations residing in Europe, and differential utilization appears mainly attributable to inequalities in preventive dental visits.
Abstract: The purpose of this study was to describe income-related inequalities in dental service utilization by the elderly populations residing in different European countries. We used data from the Survey of Health, Ageing, and Retirement in Europe (SHARE Wave 2), which contains information on utilization of dental services by 33,358 individuals aged 50+ years from 14 different countries. We assessed income-related inequalities in dental attendance and preventive and/or operative dental treatment by means of Concentration Indices (CI) and Slope Indices of Inequality (SII). We could identify a disproportionate concentration of access to treatment among the rich elderly populations in all 14 countries (relative inequality according to CI), as well as significantly higher access to treatment by individuals located in the highest in relation to the lowest income group for all countries except Italy and the Czech Republic (absolute inequality according to SII). Such differential utilization appears mainly attributable to inequalities in preventive dental visits, either alone or in combination with operative treatment. Persons’ oral health status explains substantial proportions of absolute but not of relative inequalities. Overall, there is considerable income-related inequality in dental service utilization by several elderly populations residing in Europe. More research is needed to identify the exact causes of such disparities.
TL;DR: It was concluded that dysphagia is a serious risk factor for aspiration pneumonia in frail older people, particularly in those suffering from a cerebrovascular disease.
Abstract: As part of a systematic literature review, a comprehensive literature search was carried out to identify risk factors for aspiration pneumonia in frail older people. A prominent risk factor found was dysphagia with evidence level 2a, according to the Oxford Centre for Evidence-based Medicine Levels of Evidence. Subsequently, a meta-analysis of 4 cohort, 1 case-cohort, and 1 case-control study on dysphagia as a risk factor of aspiration pneumonia in frail older people was performed. Using a random effects model, we found a positive correlation between dysphagia and aspiration pneumonia: OR = 9.84; 95%CI = 4.15 - 23.33 (test for statistical homogeneity: p < 0.001). Then, a subgroup meta-analysis was performed with 4 cohort studies, all including patients with a cerebrovascular disease. Once again, a positive correlation was found between dysphagia and aspiration pneumonia: OR = 12.93; 95%CI = 8.61 - 19.44. The test for statistical homogeneity revealed no statistically significant result (p = 0.15). It was concluded that dysphagia is a serious risk factor for aspiration pneumonia in frail older people, particularly in those suffering from a cerebrovascular disease.
TL;DR: It is demonstrated for the first time that DPSCs could be differentiated into pancreatic cell lineage and offer an unconventional and non-controversial source of human tissue that could be used for autologous stem cell therapy in diabetes.
Abstract: The post-natal dental pulp tissue contains a population of multipotent mesenchymal progenitor cells known as dental pulp stromal/stem cells (DPSCs), with high proliferative potential for self-renewal. In this investigation, we explored the potential of DPSCs to differentiate into pancreatic cell lineage resembling islet-like cell aggregates (ICAs). We isolated, propagated, and characterized DPSCs and demonstrated that these could be differentiated into adipogenic, chondrogenic, and osteogenic lineage upon exposure to an appropriate cocktail of differentiating agents. Using a three-step protocol reported previously by our group, we succeeded in obtaining ICAs from DPSCs. The identity of ICAs was confirmed as islets by dithiozone-positive staining, as well as by expression of C-peptide, Pdx-1, Pax4, Pax6, Ngn3, and Isl-1. There were several-fold up-regulations of these transcription factors proportional to days of differentiation as compared with undifferentiated DPSCs. Day 10 ICAs released insulin and C-peptide in a glucose-dependent manner, exhibiting in vitro functionality. Our results demonstrated for the first time that DPSCs could be differentiated into pancreatic cell lineage and offer an unconventional and non-controversial source of human tissue that could be used for autologous stem cell therapy in diabetes.